Micro cellular systems (MCS's) in the past have been broadly divided into two types of systems. A first type of system is one in which the transmission output from a wireless machine in a base station is reduced, thereby trying to reduce the cell radius in the cellular mobile telephone system (CMTS). This system has been implemented with the main purpose of increasing the repetition utilization efficiency of a frequency and thus of increasing the number of mobile units which can be accommodated per unit area. This system is essentially not different from the CMTS at all except that the cell radius is smaller. The frequency band used in the MCS is the same as in the CMTS and an operator of the CMTS controls and operates this system. An example of the system configuration is shown in FIG. 3.
In FIG. 3, the base station for the CMTS 101 and the base station for the MCS 102 are directly connected to the cellular switching station, or mobile telephone switching office, 103 and the control and operation of each base station, both 101 and 102, are carried out by the cellular switching station 103 in a centralized manner. Therefore, countermeasures against fraudulent use of the base stations 101 and 102 are carried out through the cellular switching station 103 and are the responsibility of an operator of the cellular switching station.
The second type of commonly used MCS is one which provides a special mobile communication service by using a frequency band which is different from that for the CMTS and has a system configuration of a miniaturized CMTS with a certain limited area as a service zone. For example, a system called a wireless PBX is a typical example of such a system configuration, as illustrated in FIG. 4. The FIG. 4 system generally uses legally defined minute transmission power, thereby making it unnecessary for a specific operator to control and operate it. A user purchases an entire system and controls and operates the system as its own private facility.
In FIG. 4, component 201 is an on-premise switching unit which is connected to a public telephone communications network, 202 is a control unit which is connected to the on-premise switching unit, 203 denotes a plurality of base stations which are connected to the control unit by wires, 204 is a mobile station which communicates by wireless connection to base station 203, and 205 is a wireless zone constituted with a plurality of base stations 203. Each of the constituting equipment and devices shown in FIG. 4 are generally small in size and light is weight, and can be easily moved and installed. Countermeasures against fraudulent use of these equipment devices are taken by each user by independent method.
In recent years, an MCS has been introduced which does not belong to either of the above-mentioned standard MCS systems. While this system utilizes the same frequency band as the CMTS, it is an independent MCS, like a wireless PBX, which avoids mutual interference with the CMTS, and therefore its system configuration is similar to that shown in FIG. 4. While an MCS of this type is installed in each user site and the ownership of the system, including the daily control and operation is carried out by the user, nonetheless the CMTS frequency band is used and a cellular operator must be responsible for the control and operation of the frequencies. An MCS of this type is small and lightweight and can, therefore, be easily moved and installed, a user can move an MCS from its initial location to another location in accordance with their needs and convenience. The disadvantage of such portability is that, unless necessary procedures for the co-existence of the MCS and CMTS are carried out properly at the new location to which the MCS has been moved, there is a possibility that the MCS will interfere with and hinder the CMTS. Of particular concern is the case in which the location to which the MCS is moved is a territory of a different cellular operator, such that a wireless facility can be operated at the new location, yet the cellular operator does not recognize and cannot control the facility's access, giving rise to serious concerns of responsibility.
It is therefore an objective of the invention to solve these conventional problems by providing a method and system for the prevention of fraudulent use by which to prevent an MCS using the same frequency band as a CMTS from being moved from its installation location to another location without permission.